What it actually is
Inside every tooth is a chamber containing the nerve and its blood supply. When decay, a crack or an injury lets bacteria in, that tissue becomes inflamed and then infected, and because it is sealed inside hard tooth it cannot swell. The pressure has nowhere to go, which is why this particular pain is the kind that no painkiller reaches.
A root canal removes the infected tissue from inside the tooth, cleans and shapes the canals it lived in, and seals them. The pain stops because the pressure and its cause are gone. The tooth stays in your mouth, which is the entire point of doing it rather than extracting.
What happens on the emergency visit
Examination and digital X-ray
The image shows which tooth is responsible, how far the infection has travelled past the root tip, and the shape of the canals inside. This is also where you find out whether the tooth is restorable at all.
You are told the plan and the price
Shown on the X-ray, explained in plain language, with the cost, before anything is started. You can say no at this point and many people ask questions here. That is normal.
Anaesthetic
A hot tooth can be harder to numb than a healthy one, which is worth knowing in advance. It is dealt with by technique and by patience, and you are not started on until you are properly numb.
The pressure is released
The tooth is opened and the infected tissue removed. This is the moment the pain goes, and for most people it is immediate and complete.
The canals are cleaned and dressed
Cleaned, shaped, disinfected, and a medicated dressing and a temporary filling placed. You go home able to sleep.
Root canal treatment is not the painful procedure of its reputation. The pain people remember is the abscessed tooth that sent them in. Modern technique under proper anaesthetic is closer to having a filling, and the relief afterwards is the part patients actually report.
One visit or two
The emergency appointment gets you out of pain and stabilises the tooth. Whether it is finished the same night or completed at a second appointment depends on the tooth, on how infected it is, and on the hour, and you will be told which applies to you.
A tooth that has had root canal treatment usually needs a crown afterwards, because removing the nerve and the tissue inside leaves it more brittle. That is planned as a normal appointment at normal prices. It is not bundled into the emergency and it is not sold to you at three in the morning.
Root canal or extraction
There are teeth that are not worth saving, and you will be told plainly when yours is one of them rather than being charged for a treatment that will fail. Generally the questions are how much sound tooth is left above the gum, whether the root is fractured, and how much bone is still supporting it.
Where a tooth can be saved it is usually worth saving. An extraction is quicker and cheaper on the night and then costs considerably more later, in an implant or a bridge, and in what the neighbouring teeth do once there is a gap to drift into.
Prices are published in advance. The emergency appointment is AED 1,500 to 2,500 all in, quoted after the X-ray and before treatment begins.